Assembly methods for medical electrical leads

ABSTRACT

A method for making a medical electrical lead electrode assembly includes the steps of: forming an insulative carrier from an insulative material; coupling at least one conductive component to the carrier by inserting a pre-formed tab of the conductive component through the carrier, from a first side thereof to a second side thereof, so that the conductive component is secured to the carrier with the tab extending along a surface of the second side of the carrier and an inward facing surface of an electrode portion of the conductive component being disposed against a surface of the first side of the carrier; coupling an elongate flexible conductor to the tab of the component; and forming an insulative layer over the second side of the carrier, the tab and the conductor electrically coupled to the tab.

RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 11/465,879, now U.S. Pat. No. 7,765,011, which was filed onAug. 21, 2006, and is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present invention is related to medical electrical leads and moreparticularly to methods for making electrode assemblies thereof.

BACKGROUND

Medical electrical leads include one or more conductors that extendwithin an elongate insulative body and are coupled to one or moreelectrodes supported by the body. The one or more electrodes aretypically mounted to a distal portion of the lead body and the distalportion positioned, or implanted, in a patient's body to provideelectrical stimulation, for example, within a pericardial space, toprovide restorative cardiac stimulation, or, within an epidural space,to provide pain-relieving spinal stimulation.

The portion of the lead body that supports the one or more electrodesshould be configured to, at minimum, allow each electrode surface tomake contact with a target stimulation site, support each joint betweenthe one or more electrodes and the corresponding conductor, and, in thecase of more than one electrode, electrically isolate the electrodes andconductors from one another. Electrode assemblies have been developed,for example, within the context of the exemplary stimulation scenariosreferenced above, wherein a ‘flattened’, or relatively thin, lead bodyportion, for example, having a patch or paddle configuration, supportsone or more electrodes, preferably an array of electrodes, that aredisposed along a major surface of the lead body portion. However thereis still a need for assembly methods that result in configurations,which meet the above criteria, and improve operational efficiency inmanufacturing.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are illustrative of particular embodiments of thepresent invention and therefore do not limit the scope of the invention.The drawings are not to scale (unless so stated) and are intended foruse in conjunction with the explanations in the following detaileddescription. Embodiments of the present invention will hereinafter bedescribed in conjunction with the appended drawings, wherein likenumerals denote like elements.

FIG. 1A is a plan view of an exemplary medical electrical lead,according to some embodiments of the present invention.

FIG. 1B is an end view of the lead shown in FIG. 1A.

FIG. 2A is a perspective view of a conductive component, according tosome embodiments of the present invention.

FIG. 2B is a plan view of a conductive component, according to someembodiments of the present invention.

FIG. 3A-B are section views taken through section line D-D of FIG. 1A,according to some alternate embodiments of the present invention.

FIG. 3C is a perspective view of a conductive component, according to analternate embodiment of the present invention.

FIG. 4A is a perspective view of an insulative carrier showing a firstside thereof, according to some embodiments of the present invention.

FIG. 4B is a perspective view of an insulative carrier showing a secondside thereof, according to some embodiments of the present invention.

FIG. 4C is an enlarged view of a portion of the carrier shown in FIG.4B.

FIG. 4D is an end view of the carrier shown in FIGS. 4A-C.

FIG. 5A is a plan view of a portion of an electrode assembly, accordingto some embodiments of the present invention.

FIG. 5B is a plan view of a portion of an electrode assembly, accordingto some alternate embodiments of the present invention.

FIG. 5C is a plan view of a portion of an electrode assembly, accordingto yet further alternate embodiments.

FIGS. 6A-B are perspective views of a conductive component, according tofurther alternate embodiments of the present invention.

FIGS. 7A-B are section views taken through section line D-D of FIG. 1A,according to further alternate embodiments of the present invention.

FIG. 8 is a flow chart outlining methods of the present invention.

DETAILED DESCRIPTION

The following detailed description is exemplary in nature and is notintended to limit the scope, applicability, or configuration of theinvention in any way. Rather, the following description providespractical illustrations for implementing exemplary embodiments of thepresent invention. Examples of constructions, materials, dimensions, andmanufacturing processes are provided for selected elements, and allother elements employ that which is known to those of skill in the fieldof the invention. Those skilled in the art will recognize that many ofthe examples provided have suitable alternatives that can be utilized.

FIG. 1A is a plan view of an exemplary medical electrical lead 10,according to some embodiments of the present invention; and FIG. 1B isan end view of lead 10. FIG. 1A illustrates lead 10 including a pair ofelongate insulative tubular bodies A and B which are terminated at aproximal end by connectors 102 and 104, respectively, and which extenddistally to terminate in an insulative paddle-shaped body 101 supportingan array of electrodes AE1-8 and BE1-8, which are arranged in threecolumns 12, 13, and 14. FIG. 1B illustrates a profile of body 101, whichhas a maximum thickness T of approximately 0.09 inch along a proximalportion 151 thereof, and a maximum thickness t of approximately 0.075inch along a length thereof that extends distally from proximal portionand corresponds with an extent of columns 12, 13, 14. The shape andprofile of body 101 makes lead 10 suitable for epidural implantation toprovide spinal cord stimulation; and the arrangement of electrodes AE1-8and BE1-8 can provide flexibility for selection of a stimulation patternfrom a variety of stimulation patterns after lead 10 is implanted,without having to physically reposition lead 10. According to anexemplary embodiment of the present invention, each electrode in columns12, 13 and 14 are spaced apart from one another, along a length of eachcolumn, by a distance x, center-to-center, which is approximately 0.120inch, and each column 12, 13, 14 is spaced apart from one another by adistance z, center-to-center, which is approximately 0.179 inch.Although the electrode array illustrated herein provides a suitableexample for preferred embodiments of the present invention, it should benoted that various alternate embodiments of the present inventioninclude any number of electrodes in any arrangement.

According to the illustrated embodiment, electrodes AE1-8 are coupled tocorresponding contacts AC1-8 of connector 102 and electrodes BE1-8 arecoupled to corresponding contacts BC1-8 of connector 104, such that eachelectrode may be independently powered when the connectors 102, 104 areplugged into a stimulation device. Although not shown, those skilled inthe art will appreciate that conductors A1-8 (FIG. 5), which couple eachof electrodes AE1-8 to a corresponding contact of connector 102, extendwithin one or more longitudinally extending pre-formed channels, orlumens, of tubular body A, and conductors B1-8 (FIG. 5), which coupleeach of electrodes BE1-8 to a corresponding contact of connector 104,extend within a similar one or more channels, or lumens, of tubular bodyB. Each of conductors A1-8 and B1-8 may be in the form of a coil orcable, being formed, for example from MP35N alloy, and each preferablyincludes an insulating jacket extending thereover, being formed, forexample, from a fluoropolymer; such conductors are well known to thoseskilled in the art of medical electrical leads. A routing of theconductors within body 101, according to one embodiment of the presentinvention, will be described below, in conjunction with FIG. 5.

FIG. 1A further illustrates, with a dashed line, a border of aninsulative carrier 200 (FIGS. 4A-D), preferably formed from a flexiblepolymer, for example, silicone rubber which may have a polyester meshpanel embedded therein. According to the illustrated embodiment, carrier200 is coupled to an insulative layer 170 to form body 101, and layer170 is preferably formed from a material similar to that which formscarrier 200. FIG. 1B further illustrates a first side 21 of carrier 200corresponding to a side of body 101 from which electrodes AE1-8, BE1-8may protrude, as illustrated; alternately, electrodes AE1-8, BE1-8 maybe flush with first side 21 or recessed within first side 21. Insulativelayer 170 is shown extending over a second side 22 (FIG. 4B) of carrier200 to form an opposite side 172 of body 101, and further extends aboutdistal portions of bodies A,B to form proximal portion 151, for example,as described below in conjunction with FIG. 5. According to embodimentsof the present invention, each electrode AE1-8, BE1-8 is a portion 413of a conductive component E, preferably formed from a 90/10Platinum/iridium alloy, various embodiments of which are described inconjunction with FIGS. 2A-B, 3A-C, 6A-B and 7A-B.

FIGS. 2A-B illustrate electrode portion 413 of component E including anoutward facing contact surface 43 and an inward facing surface 41; apair of tabs 42, 44 extend from electrode portion 413 and are adapted toextend through carrier 200 in order to couple component E thereto. FIG.2A further illustrates each tab 42, 44 including a projection 420, 440,respectively. According to some embodiments of the present invention,component E is formed, for example, by stamping, such that portion 413,tabs 42, 44 and projections 420, 440 are approximately co-planar withone another, for example as shown in FIG. 2B; then, tabs 42, 44 andprojections 420, 440 are folded or bent away from portion 413 into theconfiguration illustrated in FIG. 2A. Creases or indentations, forexample, as illustrated by dashed lines in FIG. 2B, may be formed intabs 42, 44 in order to guide subsequent folding or bending.Alternately, component E may be provided as illustrated in FIG. 2A by asingle forming step, for example, machining or any other suitableforming method known to those skilled in the art. According to exemplaryembodiments of the present invention, electrode portion 413 has alength, from tab 42 to tab 44, of approximately 0.185 inch, and a widthof approximately 0.086 inch; and tabs 42, 44 each have a thickness ofapproximately 0.005 inch, and a length, from electrode portion 413 toprojections 420, 440, respectively, of approximately 0.094 inch; andprojections each have a length of approximately 0.028.

FIG. 3A is a section view, through section line D-D of FIG. 1A, whereincomponent E is coupled to carrier 200, according to some embodiments.FIG. 3A illustrates each of tabs 42, 44, having been inserted throughopenings 212 of carrier 200, extending to second side 22 of carrier 200where tabs 42, 44 are bent toward a surface of second side 22, such thattabs 42, 44 extend along the surface of second side 22, opposite inwardfacing surface 41 of the electrode portion that is disposed against asurface of first side 21 of carrier 200, and projections 420, 440 extendtoward the surface of side 22. Pre-formed openings, for example,openings 212, may be sized to accommodate tabs 42, 44 includingprojections 420, 440, or any other tab cross-section for that matter;or, carrier 200 may be stretched to widen the pre-formed openings forinsertion of tabs 42, 44 including projections 420, 440, or tabs havinglarger cross-sections that the openings. According to alternateembodiments, tabs 42, 44 do not include projections 220, 240.Furthermore, it should be noted that embodiments of the presentinvention need not include pre-formed openings, for example, openings212 in carrier 200 for tabs 42, 44 to pass through, since tabs 42, 44may form the openings by piercing carrier 200 upon insertiontherethrough.

Referring back to FIG. 2B, a length L42, L44 of each tab 42, 44,respectively, is indicated. According to further alternate embodimentsof the present invention, length L44 is greater than length L42 suchthat when tabs 42, 44 are bent toward the surface of second side 22, tab44 overlaps tab 42, as illustrated in FIG. 3B. According to an exemplaryembodiment wherein tabs overlap, a length of electrode portion 413,between tabs 42, 44 is approximately 0.185 inch, length L44 of tab 44 isapproximately 0.195 inch, and length L42 of tab 42 is approximately0.167 inch. (Another alternate embodiment of component E is describedbelow, in conjunction with FIG. 3C. Further embodiments of component Ecoupled to carrier 200, which generally correspond to additionalalternate embodiments of component E, shown in FIGS. 6A-B, are shown inFIGS. 7A-B, and are also described below.)

According to the embodiments illustrated in FIGS. 3A-B, the surface ofthe first side 21, against which surface 41 of electrode portion 413 isdisposed, is recessed; and, with reference to FIG. 4A, it may be seenthat first side 21 of carrier 200 includes a recess 201 for eachelectrode portion 413, for example electrodes AE1-8 and BE1-8 (FIG. 1A).It should be noted that embodiments of the present invention need notinclude recesses 201. FIGS. 3A-B further illustrate a conductor 50coupled to tab 44 of component E by a joint 35, which may be anysuitable type of joint known to those skilled in the art, for example, aweld or a crimp or a combination thereof wherein a sleeve is crimped toconductor 50 and then the crimped sleeve is welded to tab 44. AlthoughFIGS. 3A-B show joints 35 formed on a surface of tab 44 that faces awayfrom second side 22, some alternate embodiments include joints formedalong a surface of a tab that faces toward second side 22 of carrier200, when the tab is bent to couple the corresponding component E tocarrier 200. According to one alternate embodiment of component E, tab44 is pre-formed to accommodate crimping of conductor 50 thereto, forexample as illustrated in FIG. 3C. FIG. 3C shows tab 44 including acurved portion 344 forming a groove 304, into which groove 304 conductor50 may be inserted for crimping therein, either prior to, or following,the bending of tab 44 to couple component E to carrier 200. It should benoted that, although tab 42 is shown, in FIG. 3C, without a similar apre-formed curve, tab 42 may also be pre-formed as tab 44.

Referring back to FIGS. 3A-B, conductor 50 is shown extending from joint35 into a pre-formed channel 55 along second side 22 of carrier. Withreference to FIG. 4B, an entirety of second side 22 of carrier 200,according to one embodiment, may be seen. FIG. 4B illustrates aplurality of pre-formed channels AG1-8 and BG1-8 (each corresponding tochannel 55 illustrated in FIGS. 3A-B and 7A-B); each channel AG1-8 andBG1-8 is shown extending from a corresponding pre-formed recess 202 thataccommodates a pair of tabs 42, 44. According to the illustratedembodiment, channels AG1-8 and BG1-8 direct each conductor 50 from thecorresponding joint 35 (FIGS. 3A and 5) into either a first or secondlongitudinally extending pre-formed channel 26, 28. FIG. 4B shows firstlongitudinally extending pre-formed channel 26 extending from each ofchannels AG1-8, and second longitudinally extending pre-formed channel28 extending from each of channels BG1-8. FIG. 4C is an enlarged view ofa portion of carrier 200 enclosed in the box shown in FIG. 4B. Withreference to FIG. 4B-C, it may be seen that a series of flaps 215 extendin a zipper-like fashion over each of channels 26 and 28; conductors 50may be pressed across flaps 215 into channels 26,28 and then held inplace by flaps 215. FIG. 4D is a distal end view of carrier 200 showingflaps 215 extending over channels 26 and 28.

FIG. 4D further illustrates a panel 25, for example, formed from apolyester mesh material, extending just beneath recessed surfaces ofsecond side 22 of carrier 200. According to some alternate embodiments,panel 25 extends just beneath an exterior surface of first side 21.According to preferred embodiments of the present invention, panel 25 isintegrally formed with carrier 200, having a foot print similar to thatof carrier 200, for example, as defined by the dashed lines in FIG. 1A,to provide some additional tear resistance to carrier 200.

FIG. 5A is a plan view of an electrode assembly 30, incorporatingcarrier 200, wherein conductors 50 (FIGS. 3A-B and 7A-B) are designatedas a first plurality A1-8 and a second plurality B1-8, and dashed linesindicate a border of insulative layer 170, which has been madetransparent in order to show a routing of conductors A1-8 and B1-8. FIG.5A illustrates both of channels 26 and 28 extending approximatelyparallel to a longitudinal axis 300 of carrier 200, channel 26 betweencolumns 12 and 13 to direct conductors A1-8 into tubular body A, andchannel 28 between columns 13 and 14 to direct conductors B1-8 intotubular body B. According to the illustrated embodiment, each joint 35is provided with some strain-relief against longitudinal loading bypre-formed channels AG1-8 and BG1-8 (FIG. 4B), which direct conductorsA1-8 and B1-8, at an angle to longitudinal axis 300, away fromrespective joints 35, and into respective longitudinal channels 26, 28.

FIG. 5A further illustrates tubular bodies A and B each including adistal portion AX and BX, respectively; and, with reference to FIG. 5Ain conjunction with FIG. 1A, it may be appreciated that portions AX andBX extend into proximal portion 151 of body 101 formed by insulativelayer 170; layer 170 may further extend into pre-formed apertures 33formed in sidewalls of portions AX, BX. It should be understood thatportions AX and BX form extensions of the one or more longitudinalchannels, or lumens, of tubular bodies A, B so that conductors A1-8 andB1-8, respectively may pass proximally therethrough from channels 26,28. FIG. 5A further illustrates each portion AX, BX including a curvedsegment 39, wherein segments 39 are longitudinally offset from oneanother, and an apex of each segment 39 is approximately aligned withone another in close proximity to longitudinal axis 300. The illustratedu-shape of each segment 39, and the arrangement of segments 39 mayfacilitate compact coupling of segments 39 to carrier 200, within layer170; however, the scope of the present invention is not so limited, andany suitable curved shape and arrangement can be incorporated inalternate embodiments. Curved segments 39 may provide additionstrain-relief and minimize flex-fatigue for the conductors A1-8, B1-8,and may further prevent longitudinal forces from dislodging electrodeassembly 30 from an implanted location. According to exemplaryembodiments, tubular bodies A, B are each formed from a polyurethanematerial and insulative layer 170 is formed from a silicone material;because silicone and polyurethane materials may not bond to one another,the mechanical interlocking between layer 170 and tubular bodies A, B,at apertures 33 and along curve segments 39, may provide additionalstructural integrity to assembly 30, for these exemplary embodiments.

FIGS. 5B-C are plan views of alternative electrode assemblies 30′ and30″, respectively. FIGS. 5B-C illustrate portions AX and BX, of tubularbodies A and B, respectively, within insulative layer 170, including nocurved segments, such as segments 39 illustrated in FIG. 5A. Accordingto the embodiment of FIG. 5B, first plurality of conductors A1-8 areformed in a bend between channel 26 and portion AX, and second pluralityof conductors B1-8 are likewise formed in a bend between channel 28 andportion BX. According to the embodiment of FIG. 5C, first plurality ofconductors A1-8 cross over from channel 26 to enter tubular body B andsecond plurality of conductors B1-8 cross over from channel 28 to entertubular body A. Conductors A1-8 and B1-8 may be held in the illustratedconfigurations by additional channels formed in carrier 200 or may bepositioned as such prior to molding of insulative layer 170 thereover.It should be noted that embodiments of the present invention may furtherinclude those in which conductors A1-8, B1-8 extend in approximatelystraight paths from channels 26 and 28 into respective tubular bodies A,B. It should be noted that each conductor of pluralities A1-8 and B1-8are electrically isolated from one another by an insulating jacketextending around each conductor.

Although FIGS. 5A-C illustrates a preferred embodiment wherein joints 35are made between a distally located tab of each component E and thecorresponding conductor, the scope of the present invention is notlimited to any particular orientation of tabs 42 and 44, with respect toproximal and distal ends 51 and 53, respectively, of carrier 200; forexample, some alternate embodiments include conductive components Eoriented in carrier such that tabs 42, 44 are disposed on opposite sidesof a longitudinal axis of the corresponding column 12, 13, 14. Accordingto further alternate embodiments, joints 35 are made with the proximallylocated tabs shown in FIG. 5A; or joint 35 may be made with a centrallylocated tab, for example, tab 46 shown in FIG. 7B for the embodiment ofcomponent E illustrated in FIG. 6B.

FIGS. 6A-B are perspective views of conductive component E, according toadditional alternate embodiments of the present invention; and FIGS.7A-B are section views taken through section line D-D of FIG. 1A,according to embodiments that generally correspond to the embodiments ofcomponents E illustrated in FIGS. 6A-B, respectively. FIG. 6Aillustrates component E including tabs 47 and 49 extending outward suchthat tabs 47, 49, when component E is coupled to carrier 200, extendalong a surface of second side 22 of carrier 200, which is offset frominward facing surface 41 of electrode portion 413, for example asillustrated in FIG. 7A. According to the illustrated embodiment, tabs47, 49 are pre-formed prior to insertion through carrier 200, however,according to an alternate embodiment, tabs 47, 49 are bent outward afterinsertion through carrier 200. Dashed lines in FIG. 6A illustrate yetanother alternative embodiment of component E, wherein tabs 47, 49extend both inward, toward one another, and outward. FIG. 6B, aspreviously described, illustrates component E including centrallylocated tab 46 extending from electrode portion 413; tab 46 is shownincluding a projection 460 which extends toward a surface of second side22 of carrier when tab 46 is bent, as illustrated in FIG. 7B. Of coursetab 46 need not include projection 460, and, according to alternateembodiments, tab 46 may be pre-formed, as shown in FIG. 7B, prior toinsertion through carrier 200. Those skilled in the art will recognizethat various numbers and configurations of tabs, extending fromelectrode portion 413 of component E, may be employed within the scopeof the present invention.

FIG. 8 is a flow chart outlining alternate methods of the presentinvention for making inventive electrode assemblies. FIG. 8 outlinesmethods wherein forming an insulative carrier, for example carrier 200,is one initial step 60 and forming each conductive component, forexample, component E, is another initial step 61. After each componentand the carrier is formed, a conductor is coupled to a tab of thecorresponding component, per step 63, either before or after eachcomponent is coupled to the carrier, per step 62. In a latter step 65,an insulative layer is formed over the carrier to encapsulate eachcomponent tab and conductor. According to preferred methods, the carrieris formed (step 60) via a molding process, for example, transfer orinjection molding, and a polymer mesh panel, for example, panel 25 (FIG.3D), is integrated into the carrier by inserting the panel into a moldprior to completing the molding process. A mold, which is used by somemethods, includes features to form openings through the carrier andchannels and recesses on first and second sides of the carrier, whichopenings, channels and recesses are described above in conjunction withcarrier 200. According to some alternate methods, a process secondary tomolding may be used to form channels and/or recesses, for example, byother types of thermal forming known to those skilled in the art, or bycutting or abrading methods, or by bonding additional layers to themolded carrier. For those embodiments of the carrier which includepre-formed openings, for example, openings 212, corresponding openingsmay be formed in the mesh panel prior to placing the panel in the mold,the panel openings being aligned with mold features for forming theopenings of carrier, when the panel is placed.

Forming each conductive component (step 61) may be performed asdescribed in conjunction with FIGS. 2A-B, and coupling each component tothe carrier (step 62) is performed by inserting one or more tabs of thecomponent through the carrier such that an electrode portion of thecomponent is disposed on the first side of the carrier and the one ormore tabs are disposed on the second side of the carrier to secure thecomponent to the carrier, for example as illustrated in FIGS. 3A-B and7A-B. The one or more tabs may be bent, after insertion through thecarrier, or pre-formed in a bent configuration, prior to insertionthrough the carrier, such that bending the tabs after insertion throughthe carrier is not required to secure the component to the carrier.According to a preferred method of the present invention, the tabs ofall of components E are bent or folded simultaneously after having beeninserted through the carrier. All the tabs may be simultaneously foldedby a plate that is pressed down toward the second side of the carrierwhile the components are supported, for example, along contact surfaces43 of electrode portions 413.

According to some methods, after each component is coupled to thecarrier (step 62), each conductor is coupled to the correspondingcomponent tab, per step 63. According to some alternate methods, eachconductor is coupled to the corresponding component tab (step 63) priorto coupling each component to the carrier (step 62). If step 62 followsstep 63, a length of the conductor may be passed through the carrierahead of the tab to couple the component to the carrier, or, theelectrode portion of the component may be passed through the carrier,ahead of the tab. Although not shown in the outline of FIG. 8, eachconductor may be routed in grooves on the second side of the carriereither before or after coupling each conductor to the correspondingcomponent tab. As previously described in conjunction with FIGS. 4B-D,FIG. 5A, and method step 60, insulative carriers, according to somepreferred embodiments of the present invention, include pre-formedchannels which are suitable for routing conductors along the carrier toinsulative tubular bodies and have features to hold conductors in placeon the carrier while the insulative layer is formed over the carrier(step 65). Such channels may further provide some strain-relief for thecoupling between each conductor and the corresponding component tab.Coupling each conductor to the corresponding component tab, per step 63,may be performed by any of the methods previously described, forexample, by crimping, welding (e.g. laser or resistance), or acombination thereof, or by any other suitable method known to thoseskilled in the art.

Once each component and corresponding conductor, coupled thereto, aremounted or coupled to the carrier, an insulative layer may be formed,per step 65, over the side of the carrier on which the component tabsand conductors are disposed. As previously described, the insulativelayer may further surround a portion of one or more elongate tubularbodies into which each conductor has been inserted, for example,portions AX, BX of tubular bodies A, B shown in FIGS. 5A-C. Eachconductor may have been inserted into the corresponding tubular memberat any point, before step 65, in the method outlined by FIG. 8, that is,before or after any of steps 60, 61, 62, and 63. According to somemethods of the invention, prior to insertion of each conductor into thecorresponding tubular body, each tubular body is thermal formed toinclude a curved segment, for example segment 39, shown in FIG. 5A, andmay also be perforated to include an aperture, for example aperture 33,also shown in FIG. 5A. Forming the insulative layer (step 65) ispreferably performed by an over-molding process, for example, either byinjection molding or transfer molding. According to the over-moldingprocess, the carrier on which each electrode and corresponding conductorare mounted, along with each tubular body, in which each correspondingconductors has been inserted, are placed in a mold, and an insulativematerial, preferably silicone rubber, is injected into the mold to covereach conductor and component tab, for example, along second side 22 ofcarrier 200, and to surround each tubular body, for example, asillustrated in FIGS. 1A and 5A-C.

In the foregoing detailed description, the invention has been describedwith reference to specific embodiments. However, it may be appreciatedthat various modifications and changes can be made without departingfrom the scope of the invention as set forth in the appended claims.

The invention claimed is:
 1. A method for making a medical electricallead electrode assembly, the method comprising: forming an insulativecarrier from an insulative material, the carrier including a first sideand a second side, opposite the first side, and the carrier being formedto include an opening therethrough, from the first side to the secondside; coupling a conductive component to the carrier by inserting apre-formed tab of the conductive component through the opening in thecarrier, from the first side to the second side of the carrier, so thatthe conductive component is secured to the carrier with the tab of theconductive component extending along a surface of the second side of thecarrier and an inward facing surface of an electrode portion of theconductive component being disposed against a surface of the first sideof the carrier, the inward facing surface being opposite an outwardfacing contact surface of the electrode portion; electrically couplingan elongate flexible conductor to the tab of the conductive component;and forming an insulative layer over the second side of the carrier,over the tab of the conductive component and over the conductorelectrically coupled to the tab.
 2. The method of claim 1, whereinelectrically coupling the conductor to the tab precedes coupling theconductive component to the carrier.
 3. The method of claim 1, whereinthe insulative carrier is further formed to include a recess in thesurface of the first side thereof, the recess receiving the electrodeportion of the conductive component when the conductive component iscoupled to the carrier.
 4. The method of claim 1, wherein the insulativecarrier is further formed to include a recess in the surface of thesecond side thereof, the recess receiving the pre-formed tab when theconductive component is coupled to the carrier.
 5. The method of claim1, wherein the insulative carrier is further formed to include a channelin the surface of the second side; and further comprising routing theconductor within the channel, prior to forming the insulative layer overthe second side of the carrier.
 6. The method of claim 1, whereinelectrically coupling the conductor to the tab of the conductivecomponent comprises welding.
 7. The method of claim 1, wherein: thepre-formed tab includes a groove; and electrically coupling theconductor to the tab comprises inserting the conductor into the grooveof the tab and crimping the conductor therein.
 8. The method of claim 1,wherein the surface of the second side of the carrier, along which thetab extends, when the conductive component is coupled to the carrier, isopposite the surface of the first side of the carrier, against which theinward facing surface of the electrode portion is disposed.
 9. Themethod of claim 1, wherein the surface of the second side of thecarrier, along which the tab extends, when the conductive component iscoupled to the carrier, is laterally offset from the surface of thefirst side of the carrier, against which the inward facing surface ofthe electrode portion is disposed.
 10. The method of claim 1, furthercomprising: forming a slit in a mesh panel; and placing the mesh panelin a mold, the mold including features for forming the opening throughthe carrier; wherein forming the insulative carrier comprises moldingthe insulative material over the mesh panel in the mold such that theopening formed through the carrier corresponds in position to the slitformed in the mesh panel.
 11. The method of claim 1, further comprising:forming a bend in a tube and an aperture through a sidewall of the tube,prior to forming the insulative layer; coupling the tube to the carrierby forming the insulative layer, such that the insulative layer extendsover the bend in the tube and through the aperture in the sidewall ofthe tube; and inserting the elongate flexible conductor into the tubeprior to coupling the tube to the carrier.